A kind of preparation method of polysaccharide dispersion liquid

Abstract

The invention discloses a preparation method of polysaccharide dispersion liquid, and relates to polysaccharide. The preparation method includes the following steps that 1, polysaccharide is subjected to exchange with a solvent and then dried; 2, a DMAc / LiCl solution with the mass concentration of LiCl being 2%-6% is prepared with DMAc as a solvent, the activated and dried polysaccharide obtained in the step 1 is added, heterogeneous polysaccharide dispersion liquid is obtained, LiCl is added to make the total mass concentration be 3%-20%, and the polysaccharide dispersion liquid is obtained. It is avoided that the high temperature condition is adopted, degradation of cellulose and chitin and solvent volatilization can be effectively prevented, and energy saving and equipment cost reduction can be achieved due to the low temperature and normal pressure conditions; LiCl is added in two steps, part of time for dissolution of LiCl is saved, the caking and gathering problem especially in the dissolution process in preparation of a high-concentration cellulose solution is completely solved, and dissolution time is greatly shortened.

Description

technical field [0001] The invention relates to polysaccharides, in particular to a method for preparing polysaccharide dispersions. Background technique [0002] Polysaccharides such as lignocellulose have the characteristics of abundant and easy-to-obtain raw materials, easy degradation, renewable, low price, and environmental friendliness. As a renewable resource, the high-value utilization of lignocellulose and chitin can bring huge economic benefits in light industry, materials, energy, chemical industry, food and other industries. Due to the presence of a large number of intramolecular and intermolecular hydrogen bonds in the structure, it is difficult to be dissolved by conventional reagents. However, in a homogeneously dissolved state, the reaction between the hydroxyl groups on the polysaccharide chains such as lignocellulose and the derivatizing reagent will become more efficient and uniform. Therefore, the research on the dissolution system of polysaccharides su...

AI Technical Summary

Problems solved by technology

[0007] There are two problems in the dissolution of cellulose activated at low temperature: (1) it takes a certain time (within 1 h) to completely dissolve 6-9 wt% LiCl in DMAc at low temperature, which virtually increases the time required for the dissolution process, Although heating can shorten this part of the time, the DMAc solution is easy to turn yellow; (2) there is a certain bond between the activated cellulose particles, no matter whether the DMAc / LiCl solvent is added to the cellulose or the cellulose is added to the solvent In the process, due to the slow dispersion, the cellulose that is easy to bond will have more agglomerated clusters suspended in the surrounding transparent solution, especially when dissolving cellulose extracted from lignocellulose or dissolving a large amount of fiber When the viscosity of the dispersion system increases, the stirring effect gradually deteriorates. This problem is particularly obvious. At this time, it is difficult for these agglomerated groups to be dissolved quickly. To completely dissolve, one is to prolong the dissolution time, and the other is to Only by strengthening high-speed and high-strength mechanical stirring can LiCl / DMA slowly penetrate into the inside of the agglomerate to achieve gradual dissolution, which causes great difficulties for the use of cellulose

[0009] In addition, unlike the high-temperature activation process, if the cellulose is directly added to the pure DMAc solution without LiCl at low temperature, the dispersion effect is poor, and the solid-liquid phase separation is obvious, and then LiCl is added at one time. This method takes a long time. After a period of time, it is still difficult to obtain a completely homogeneous cellulose dispersion, and the dissolution effect is poor